In 1630 at the beginning of European settlement, about 425,000,000 hectares of the United States were covered with trees. By 2017, the area covered by trees was reduced to 300,000,000 hectares. What is the percentage decrease in the area covered by trees between 1630 and 2017?
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Physics, 22.06.2019 12:30
Hydrogen atoms are excited by a laser to the =4n=4 state and then allowed to emit. what is the maximum number of distinct emission spectral lines (lines of different wavelengths) that can be observed from this system? 8 6 2 7 4 5 1 3 calculate the wavelength of the 4⟶14⟶1 transition. =λ=
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Physics, 22.06.2019 18:30
Which form of cell division creates the sperm and egg, resulting in half of the chromosomes as the other cells?
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Physics, 22.06.2019 19:00
Which of the following list the divisions of the geologic time scale in order from longest to shortest
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In 1630 at the beginning of European settlement, about 425,000,000 hectares of the United States wer...
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